Russia‘s president has threatened to deploy missiles to target the US missile shield in Europe if Washington fails to give a legal guarantee that it will not be aimed against country’s nuclear forces.

Dmitry Medvedev has accused the US and its Nato allies of ignoring its concerns over America’s proposed missile defence system and said Russia would have to take military countermeasures if it did not receive the assurances it desired.

The president said he still hoped for a deal with the US on missile defence, but delivered a harsh warning that Moscow would take action if the shield continued to be built without a binding agreement outlining it would not be aimed against Russia.

The US has repeatedly assured Moscow that its proposed missile defence system would not be directed against Russia’s nuclear forces and reinforced its stance again. “I do think it’s worth reiterating that the European missile defense system that we’ve been working very hard on with our allies and with Russia over the last few years is not aimed at Russia,” said Capt. John Kirby, a Pentagon spokesman. “It is … designed to help deter and defeat the ballistic missile threat to Europe and to our allies from Iran.”

But Medvedev said Moscow would not be satisfied by simple declarations and wants a legal guarantee setting out the boundaries. He added: “When we propose to put it on paper in the form of precise and clear legal obligations, we hear a strong refusal.”

He warned that Russia would station missiles in its westernmost Kaliningrad region and other areas if the US continued its plan without offering a firm pledge that the shield would not be directed at its nuclear forces. It is unclear whether the missiles would carry conventional or nuclear warheads.

The missile shield has long been a subject of dispute between Moscow and Washington. The Obama administration has repeatedly said the shield is needed to fend off a potential threat from Iran, but Russia fears it could erode the deterrent potential of its nuclear forces.

“If our partners tackle the issue of taking our legitimate security interests into account in an honest and responsible way, I’m sure we will be able to come to an agreement,” Medvedev said. “But if they propose that we ‘cooperate,’ or, to say it honestly, work against our own interests, we won’t be able to reach common ground.”

Moscow has agreed to consider a proposal Nato made at the Lisbon summit in November last year to cooperate on the missile shield, but the talks have reached a stalemate over how the system should be operated. Russia has insisted that it should be run jointly, which Nato has rejected.

Medvedev also warned that Moscow may opt out of the New START arms control deal with the United States and halt other arms control talks, if the US proceeds with the missile shield without meeting Russia’s demand.

The US had hoped that the START treaty would stimulate progress in further ambitious arms control efforts, but such talks have stalled because of tension over the missile plan.

Medvedev said that Russia will carefully watch the development of the US shield and take countermeasures if Washington continues to ignore its concerns.

He warned that Moscow would deploy short-range Iskander missiles in Kaliningrad, a Baltic Sea region bordering Poland, and place weapons in other areas in Russia’s west and south to target US missile defence sites.